Which of the following statements about the response of arteriolar smooth muscle to changing oxygen partial pressures is TRUE?
A. Both systemic and pulmonary arterioles respond to a decrease in PO2 by constricting.
B. Both systemic and pulmonary arterioles respond to a decrease in PO2 by dilating.
C. Systemic arterioles respond to a decrease in PO2 by dilating, but pulmonary arterioles constrict in response to decreased PO2.
D. Systemic arterioles respond to a decrease in PO2 by constricting, but pulmonary arterioles dilate in response to decreased PO2.
E. Changes in PO2 do not affect arteriolar smooth muscle in the pulmonary system.
C
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